CVE-2026-109399SWUpdate through 2026.05.1 CMS Signature Verification Bypass via Embedded Intermediates
Updated under an hour ago ()
Does this affect you?
It affects sbabic swupdate. Add what you run to find out whether that includes you.
EPSS puts the chance of exploitation in the next 30 days at 0.21%, higher than 10% of scored CVEs.
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SWUpdate through 2026.05.1 contains an improper certificate validation vulnerability in crypto/swupdate_cms_verify_openssl.c that trusts untrusted X.509 certificates embedded in CMS SignedData for chain building. Attackers holding a signing key from a sibling intermediate under the same root can embed that intermediate in the signature to install malicious updates.
- CVSS
- 8.1 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-295
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 0.21% (percentile 10)
- Assigned by
- VulnCheck
- NVD analysis
- Deferred
- Record last updated
- Oct 18, 2026
- First seen by InfoSec Signals
- Oct 12, 2026
Affected products
sbabic swupdate sbabic:swupdate (from the name) | through 2026.05.1 | CNA record |
References
- https://groups.google.com/g/swupdate/c/dsoMcGFnEnstechnical-description, mailing-list
- https://github.com/sbabic/swupdate/commit/e66c5640664a31668926a24c0c84b6b6570dc0d9patch
- https://github.com/sbabic/swupdate/blob/2026.05.1/crypto/swupdate_cms_verify_openssl.ctechnical-description
- https://github.com/sbabic/swupdateproduct
- https://www.vulncheck.com/advisories/swupdate-through-2026.05.1-cms-signature-verification-bypass-via-embedded-intermediatesthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.